How they could've made Episode 5 more emotional..

.. If I was writing the episode, what I would've done. After killing the stranger, I would've had Ed still a zombie, and meeting Diana somewhere. Lee, Clementine and Diana start talking and then Diana gets devoured somehow. Something along the lines of that. I know I don't make it sound good, but I'm sure TT could've made that good (I always wanted to see Clem's parents alive.)

No, zombies are drawn to familiar aspects of their previous lives...at least, if the TV show is to be believed, they are. Hence Morgan's wife returning to their house over and over. They might have just shambled along next to each other...not retaining memories, obviously.